The invention relates to an intramedullary nail for distraction of a long bone and a modular system.
Intramedullary nails that enable distraction of long bones are known from the prior art. Two bone fragments, a distal fragment and a proximal fragment are displaced relative to one other by means of an intramedullary nail. It is intended for new bone to grow at the point of contact between the two bone fragments. This is achieved by selecting a rate of advance of the intramedullary nail that is sufficiently slow to allow distraction to take place.
It is also known from the prior art to use intramedullary nails that are capable of effecting segment transport, for example the prior art in DE 197 08 279 C2 may be cited here. Such segment transport enables the treatment of large bone defects, of more than 3 cm for example, such as can occur as a consequence of disease or through the effect of force. Large bone defects can also occur in surgical procedures necessitated by bone tumours, and these may also be treated with an intramedullary nail with segment transport depending on the severity of the disease.
A fundamental challenge in the case of intramedullary nails with segment transport is the fixing of the ends of the intramedullary nail in the proximal bone fragment and in the distal bone fragment. Another challenge is stabilisation against rotation.
Thus, DE 197 08 279 C2 suggests a guide sleeve that is fixed in the bone fragment with a screw screwed in in the axial direction of the long bone. As an additional component, the guide sleeve makes the fitting of the intramedullary nail in the bone complicated. The guide sleeve also requires additional clearance in the bone fragment so that the diameter of the opening that has to be created in the bone is large. Furthermore, due to its design the intramedullary nail of the prior art cited above cannot be used for lower leg bones.
The object of the invention is to describe an intramedullary nail or a modular system for an intramedullary nail that improves the systems or intramedullary nails known from the prior art, in particular the drawbacks of the prior art are to be alleviated or eliminated. Desirable are intramedullary nails that require as little surgical effort as possible or enable reliable fixation in the bone fragments. A modular system should be able to be flexibly adapted to different circumstances, for example different bones or different applications such as segment transport or distraction.